Gun firing system



Feb. 4, 1947. A. P. DAVIS ETAL. 2,415,126

GUN FIRING SYSTEM Filed Aug. 25, 1944 Patented Feb. 4, 1947 2,415,126 GUN Flame, SYSTEM Arthur P. Davis, New York, and George Agins,

Brooklyn, N. Y., assignors to Arma Corpora.- tion, Brooklyn, N. Y., a corporation of New York Application August l25, 1944, Serial No. 551,135

12 Claims.

This invention relates to gun ring systems and has particular reference to `an harmonic system for `firing a gun from the rolling deck of a ship, at a predetermined point in the roll, and the present `application is a continuation-impart of application Serial No. 248,266, filed December 2 9, 1938. v

In modern naval gun firing technique, the recontrol problem is solved for one chosen position in roll of the ship, generally the even keel position, and as the ship rolls through this position, the gun is iired by automatic contact mechanism of which the present invention is an improved form. inasmuch as the gun is fired by electrical ignition of powder, best results are obtained whe:` the total amount of heat generated by the iiring current is constant, so that the firing contacts must be in engagement for a certain constant time determined by the characteristics of the gun, regardless of the speed of roll of the ship` A simple contact operated by the rolling of the ship is not adequate for this purpose., since the varying speed of roll of the ship would cause a varying contact period.

In accordance with the present invention, a gun firing system is provided in which the period of engagement of the ring contacts is constan., regardless of the speed of roll of the ship, so that a wide movement of a contact-engaging element in response to a roll does not result in a longer period of contact engagement than does a short movement thereof.

In a preferredvembodiment of the invention, a pivoted contact-engaging lever, actuated in accordance with the roll of the ship, is weighted and balanced by a spring so that its natural period of oscillation is such that its time interval of swing is constant regardless of its amplitude. A contact carried or actuated by this lever cooperating with a second contact affording no restraint on the `free swing of the lever, results in a `contact engagement period which is a function of the inertia and vresilience of the lever, and is unaffected by the amplitude of its swing. The harmonic lever thus makes use of the principle of resonance.

"For a more complete understanding of the invention, reference may be had to the accompanying drawing, in which:

Figure 1 is a schematic showing of a typical form of a naval gun-firing contact-making switch embodying :the present invention.

Fig. ,2 isa curve graphically illustrating the relation between the face of the cam and the en- 2 gaged cam follower for one `form of cam contour; and

Fig. 3 graphically illustrates the relation between the face of the cam and the engaged cam follower, for a diiTerent cam contour.

Referring to Fig. 1 of the drawing, numeral I0 designates the switch, whose contacting elements are connected in series in the gun firing circuit, not shown, and are adapted to be engaged by means of a cam .II actuating a cam follower I2, in a manner to be described. Cam Il is secured to gear I3 which meshes with gear vIII which is carried by the output shaft I5 of a mechanical differential I6. One input member of differential IS is driven by gear Il of a rotating,shaft I8, which, for purposes of this invention, will be considered as the controlling element and may be actuated in accordance with the roll of the ship, such as by the level or cross-level angle mechanism of the gun director, as is determined by suitable instruments in accordance with usual practice. The other input member of the differential I6 is actuated by gear I9 mounted on shaft 2l) and carryingV a suitable dial 2l cooperating with a stationary index 22, so that the angular position of the shaft 20 may be read on dial 2|. Handle 23 is provided on shaft 2U for changing the position of gear I3 and its attached cam II to any preselected angular position, as indicated on dial 2 I. While shaft 2D is illustrated as being manually operated by handle 23, it may be adjusted by suitable mechanism if desired. It will be observed that when handle 23 is at rest, gear I3 will be driven directly through differential I6 at an angular velocity which is proportional to the angular velocity of controlling element shaft I8, shaft 20 being locked -by any suitable means, not shown, so that the lateral or side gears of the differential roll around the lower differential gear by controlling element `I8 when shaft 2D is at rest.

A disc 82 of insulating material, about which gear I3 rotates, carries the switch Ill and cam follower I2 in such a way that the tip of follower I2 lies in position for cooperation with cam II, being rigidly secured to the contact member 63 of the switch I. Contact member 63 carries contact 65, insulated therefrom, and is pivotally mounted at S4 on disc 62. The cooperating contact member 68 of the switch IIJ is mounted on the free end of spring 66 supported at its other end by post 61 on disc 62.

In the inoperative position of switch Ill, with cam I l disengaged from cam follower I2, a very small air 'gap is provided between cooperating,

contacts 65 and 68, which are positioned in the firing circuit of the gun or guns in the given illustrative example, as indicated in Fig. 1. The external electrical connections to the switch I6 are made by means of suitable feed brushes and slip rings, not shown, but of conventional construction. A very light compression spring 58 resiliently holds contact memberv 63 normally disengaged from contact 68 and a stop pin 6I on disc 62 limits the movement of the member 63 by spring 58. Spring 58 exerts just enough pressure to keep the contact member 63 against stop 6 I Ywhen the contact member 63 isin inoperative condition. Contact member 63 is weighted and balanced by spring 58 so that its natural period of oscillation is such that its time interval of swing is constant regardless of its amplitude.

Cam I I is so positioned on gear I3 as to engage cam follower I2 when the rotation of gear I3 and counter rotation of disc 62 brings cam I I and cam follower I2 into coincidence. The axis of the cam II is on a radius of gear I3 and its two faces 69 and 'III are identical, but reversed, so that the cam actuates follower I2 in the same wayfor both directions of rotation of the controlling element I 8. The relationship between cam II and cam follower I2, when they are in engagement, is as illustrated in Fig. 2, and the faces of cam I I are of the form r=ak02, in polar coordinates, where a is the distance from the axis of rotation of gear I3 to the lowest point on the rising cam which shows that the acceleration of the cam follower I2 is proportional to the angular velocity of the cam II, and that the acceleration of the cam follower is constant for constant angular velocities of the cam, so that the wear on the cam faces and cam follower will be kept at a minimum value. When the rotational path of the cam I I is large compared to the size of the cam, a parabolic face cam may be used. The relationship between a parabolic cam and its cam follower is illustrated in Fig. 3, with the cam faces being of the form y=cm2, in rectangular coordinates. Therefore with the relative movement between cam I I and cam follower I2 along the :1J-:1: axis producing a displacement of cam follower I2 along the y-y axis. The equation is substantially correct, because the rotational path of cam II is large compared to the size of the cam, so that Y t2-2v c then shows that the acceleration of cam follower I2 along the y-y axis isproportional to the velocity of cam II along the :v -1L' axis, and that the acceleration of the cam follower along the yf-y axis is constant for constant velocities of i movement of the cam. Accordingly, the wear on the cam faces and cam follower will be kept at a minimum value.

In the operation of the switch as illustrated in Fig. 1, a position of cam II with respect to cam follower I2 is selected by turning handle 23 until the desired position of the controlling element I8, at which the switch contact engagement should occur, is indicated by pointer 22 on dial 2|. In the example given the position selected for cam I I depends upon the gun fire delay which it is desired to compensate for, and the dial 2I may accordingly be graduated in units of time. Rotation of handle 23 effects rotation of gear I3 through shaft 26, gear I9, shaft I5 and connected gear I4, so that cam II will be turned to the preselected position. During this manual adjustment, the upper gear of the differential I6 is locked by gear I'I on controlling element I8.

Then, upon movement of the controlling element I8, the upper input member of differential 6 is rotated by gear I'I and as the lower gear ofI differential I6 is locked by gear I6, the differential output shaft I5 and gear I4 will rotate, so'that gear I3 with its attached cam I I revolves with an angular velocity corresponding tothe velocity of the controlling element I8, which is proportional to the velocity of roll or pitch of the ship. By reason of the differential I6, the relative position of cam I I may be changed during rotation of controlling element I8, by adjusting handle 23, the resultant movement being added to or subtracted from the driven movement of gear I 3, as the case may be, so that the gun ring time may be adjusted relative to the roll and any desired fire delay compensation may be introduced.

When the cam I`I engages the cam follower I2 at constant velocity, the cam follower I2 will be moved by the face of the cam II at a constant acceleration, and when the cam follower I2 reaches the top of the cam II, contact 65 will engage contact 68 to close the firing circuit of the gun or guns.

At the instant when the contacts 65 and 68 engage, the contact member 63 will have an angular momentum about pivot 64, and, as the comparatively considerable mass of the contact mein'- ber 63 is constant its angular momentum will be proportional to its angular velocity. Contact spring 66 will therefore be deflected by the engagement of its contact 68 by contact 65 an amount which is proportional to the angular momentum of contact member 63. However, the period of time during which the contacts 65 and 68 are engaged will be constant under all conditions since it is independent of all factors eX- cept the mass of the lever 63 and the resiliency of cooperating spring 58 which form an harmonic system, as above described.

when the end of the mitm hair period of vi;

bration of the aforementioned harmonicsystem is reached, contact 65, under the restoring force.. of spring 56, will disengage contact 68, and .con,

Although a preferred embodiment of the invention has been illustrated and described herein, it is to be understood that the invention is not limited thereby, but is susceptible of changes-in form and detail claims` l l mem-4 within the scope of the appended.

Weclaim:

1. In an harmonic system for firing a gun mounted on an unstable platform, the combination of relatively movable iirst and second members, means adapted for relatively moving said members in accordance with the movement of the platform, a swingable element on one of said members having a constant period of oscillation regardless of the amplitude of its oscillation and having an actuating portion, a contact carried by said element, a second contact resiliently mounted on said one member and in spaced relation to said first contact, a gun ring circuit including said contacts, and means on the otherl member for actuating said portion of said element to cause the element to engage its contact with said second contact at a predetermined point in the relative movement between said members and for `a predetermined constant time interval independently of the velocity of the relative movement between said members.

2,. In an harmonic system for iiring a' gun mounted on an unstable platform, the combination of relatively movable rst and second mem bers, means adapted for relatively moving said members in accordance with the movement of the platform, a swingable element on one of said members and having an actuating portion, a spring balancing the mass of said element to cause it to have a constant period of oscillation, regardless of the amplitude of its oscillation, a

contact carried by said element, a second contact resiliently mounted on said one member and in spaced relation to said first contact, a gun firing circuit including said contacts, and `means on the other member for actuating said portion of said element to cause the element to engage its contact with said second contact at a predetermined point in the relative movement between said members and for a predetermined constant time interval independently of the velocity of the relative movement between said members.

3. In an harmonic system for firing a gun mounted on an unstable platform, the combination of relatively movable rst and second members, means adapted for relatively moving said members in accordance with the movement of the platform, a swingable element on one of said members having a constant period of oscillation regardless of the amplitude of its oscillation and having an actuating portion, a contact carried by said element, a second contact resiliently mounted on said one member and in spaced relation to said first contact, a gun ring circuitl including said contacts, and cam on the other member for actuating said portion of said element to cause the element to engage its contact with said second contact at a predetermined point in the relative movement between said members and for a predetermined constant time interval independently of the velocity of the relative movement between said members.

4. In an harmonic system for firing a gun mounted on an unstable platform, the combination of relatively movable first and second members, means adapted for relatively moving said members in accordance with the movement of the platform, a swingable element on one of said members having a constant period of oscillation regardless of the amplitude of its oscillation, a contact carried thereby, a second contact resiliently mounted on said one member and in spaced relation to said first contact, a gun ring circuit including said contacts, a follower on said element, and means on the other member for actuating said follower proportionally at the velocity of movement between said members to swing said element to cause it to engage its contact with said second contact at a predetermined point in the relative movement between said members and for a predetermined constant time interval independently of the velocity of the relative movement between said members.

5. In an harmonic system for firing a gun mounted on an unstable platform, the combination of relatively movable rst and second members, means adapted for relatively moving said members in accordance with the movement of the platform, a swingable element pivoted on one of said members and having an actuating portion, a spring engaging said element for balancing the mass thereof to cause it to have a constant period of oscillation regardless of the amplitude of its oscillation, a contact carried by said element, a second contact resiliently mounted on said one member and in` spaced relation to said first contact, a gun ring circuit including said contacts, and means on the other member for actuating said portion of said element to cause the element to engage its contact with said second contact at a predetermined point in the relative movement between said members and for a predetermined constant time interval independently of the velocity of the relative movement between said members.

6. In anV harmonic system for firing a gun mounted on an unstable platform, the combination of relatively movable first and second members, means adapted for relatively moving i said members in accordance with the movement of the platform, a swingable element on one of said members having a constant period of oscillation regardless of the amplitude of its oscillation and having an actuating portion, a contact carried by said element, a second contact resiliently mounted on said one member and in spaced relation to said rst contact, a gun firing circuit including said contacts, and means on the other member for actuating said portion of said element to cause vthe element to engage its contact with said second contact at a predetermined point in the relative movement between said members and for a predetermined constant time interval independently of the velocity of the relative movement between said members and means for orienting said means to change the time of engagement of said contact during the relative movement between said members.

7. In an harmonic system for iiring a gun mounted on an unstable platform, the combination of relatively movable members, means adapted for relatively moving said members in accordance with the movements of the platform, a pair of contacts on one of said members, an harmonically oscillable lever on said one member for engaging said contacts and having an actuating portion, a cam on the other member for actuating said lever portion to cause the lever to oscillate and engage said contacts upon coincidence of the lever portion and cam during a predetermined position of said members in their relative movement. the contour of said cam effecting constant acceleration of said lever for constant relative velocity of said cam, whereby said harmonic oscillation of said lever causes the contacts to remain in engagement for a predetermined constant time interval after the lever has been actuated and independently of the velocity of the relative movement between said members.

8. In an harmonic system for ring a gun mounted on an unstable platform, the combination o1" relatively moving members, means for relatively moving said members in accordance with the movements of the platform, a pair of contacts on one of said members, a lever on said one member having a constant period oi oscillation for engaging said contacts and having an actuating portion, and a cam on the other member for actuating said lever portion to cause the lever to engage said contacts upon coincidence of the lever portion and cam during a predetermined position of said members in their relative movement, the contour of said cam effecting constant acceleration of said lever for constant relative velocity of said cam, whereby the oscillation of said lever causes the contacts to remain in engagement for a predetermined constant time interval after the lever has been actuated.

9. In an harmonic system for firing a gun mounted on an unstable platform, the combination of relatively moving members, means for moving one of said members relatively to the other member in accordance with the movement of the platform, a pair of contacts on one of said members, a lever pivoted on said one member and having a constant period of oscillation for engaging said contacts, an actuator for said lever, and a cam on said other member lying in the path of relative movement of said actuator for actuating said lever to effect engagement of said contacts at a predetermined point in the relative movement of said members, the contour of said cam effecting constant acceleration of said lever for constant relative velocity of said cam,

whereby said oscillation of said lever causes said contacts to remain in engagement for a predetermined constant time independently of said velocity. I

10. In an harmonic system for energizing the firing circuit of a gun mounted on an unstable platform, the combination of a number having a contact thereon located in said circuit, a lever pivoted on the member having a constant period of oscillation and having an actuating portion, a second contact on said member and located in said circuit, a second member relatively movable with respect to the rst member, a cam thereon adapted to engage said lever portion during said relative movement to cause said lever to oscillate, means for relatively moving said members in accordance with the movement of said platform to cause said cam and lever portion to engage and close said contacts for a constant interval, and means for adjusting the relationship between said members to vary the time of engagement between said camand lever portion.

11. In an harmonic system for energizing the tiring circuit of a gun mounted on an unstable platform, the combination of a member having a contact thereon located in said circuit, a lever pivoted on the member having a constant period of oscillation and having an actuating portion, a second contact on said member and located in said circuit, a second member relatively movable with respect to the rst member, a cam thereon adapted to engage said lever portion during said relative movement to cause said lever to oscillatemeans adapted for relatively moving said members in accordance with the movements of the platform to cause said cam and lever portion to cause said lever to engage and close said contacts for a constant interval, and means for adjusting the relationship between said members to vary the time of engagement between said cam and lever portion, said cam having a curvature such that said lever is moved thereby at constant acceleration for contact velocity of relative movement between said members.

12. In an harmonic system for energizing the ring circuit of a gun mounted on an unstable platform, the combination of a member having a Contact thereon located in said circuit, a lever pivoted on the member having a constant period of oscillation and having an actuating portion, a second contact on said member and located in said circuit, a second member relatively movable with respect to the rst member, arcam4 thereon adapted to engage said lever portion during said relative movement to cause said lever to oscillate, means for relatively moving said members relatively in accordance with the movements of the platform to cause said cam and lever portion to engage, and means for adjusting the relationship between said members to vary4 the time of engagement between said cam and lever, said cam having two operative surfaces for engaging said lever portion during opposite directions of movement between said members.

, AR'I'HUR P. DAVIS.

GEORGE AGINS.

REFERENCES CITED The'following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,387,440 Akemann Aug 9, 1921 1,445,191 Akemann Feb. 13, 1923- 

